Panasonic CT-27D10B Service Manual

Also see for CT27D10DB - 27" COLOR TV: User guide

Panasonic CT-27D10B Service Manual Manual pdf 25 page image

- 25 -Color Temperature Adjustment(B/W Tracking)Serviceman DAC Adjust. (C0) (C1) (C2) (C4) (C5)Minor Touch-Up MethodOBSERVE low and high brightness areas of a B/Wpicture for proper tracking. Adjust only as required for“good gray scale and warm highlights”.1. LOW LIGHT areas – In Serviceman Mode formaking electronic adjustments, select Cutoff (C0)RED, (C1) GRN, (C2) BLU and adjust the picturefor gray.2. HIGH LIGHT areas – In Serviceman Mode formaking electronic adjustments, select Drive (C4)GRN, (C5) BLU and adjust the picture for warmwhites.Complete AdjustmentPreparation:1. Turn the Receiver “ON” and allow 10 minuteswarm up at high brightness.2. Apply a color bar signal with color “OFF”.3. Turn the SCREEN control (part of FBT T551) fullycounterclockwise.Procedure:Preset the following Serviceman DACs for best results:• C0 . . . . . . . . . . . . . .128• C1 . . . . . . . . . . . . . 128• C2 . . . . . . . . . . . . . .128• C4 . . . . . . . . . . . . . . 64• C5 . . . . . . . . . . . . . . 641. Connect the oscilloscope to C1-1 (CRT-Board).2. In Serviceman Mode for making electronicadjustment, select the Sub-Bright DAC (B2).3. Press the R-Tune key on the remote.4. Observe the oscilloscope waveform at Horizontalrate and adjust the Serviceman Mode Sub-BrightDAC (B2) level until a scanning period of 2.5Vabove DC ground is measured, as indicated inFig. 22.5. Connect the scope to RED Cathode (KR) on theCRT-Board.6. In the Serviceman Mode for making electronicadjustments, select the RED CUTOFF DAC (C0).7. Press the R-Tune key on the remote.8. View scope trace at Horizontal rate and adjust theServiceman Mode DAC (C0) level until a scanningperiod of 195V above DC ground is measured, asindicated in Fig. 23.9. Connect the scope to the GRN Cathode (KG).10. In Serviceman Mode for making electronicadjustments, select the GRN CUTOFF DAC (C1).11. Press the R-Tune key on the Remote12. View the scope trace and adjust the ServicemanMode DAC (C1) for the scanning period to be 195Vabove DC ground. (See Fig. 23)13. Connect the scope to the BLU Cathode (KB).14. In Serviceman Mode for making electronicadjustments, select the BLU CUTOFF (C2).15. Press the R-Tune key on the Remote.16. View the scope trace and adjust the ServicemanMode DAC (C2) for the scanning period to be 195Vabove DC ground. (See Fig. 23)17. Turn the Screen Control (part of FBT) slowlyclockwise until a color horizontal line appears.18. With the other two colors Serviceman Mode DACCUTOFF adjustments (C0) RED, (C2) BLU;increase the colors to create a white horizontal line.19. Confirm that a good gray scale is established byviewing B/W color bar pattern.20. In the Serviceman Mode for making electronicadjustments select the DAC DRIVE adjustments(C4) GRN, (C5) BLUE and adjust for warm white ina white color bar pattern.21. EXIT the Serviceman Mode.22. Adjust the Picture Menu Video Adjustments Brightand Picture from low scale to high scale and checkBlack and White tracking.23. If correction is needed: Re-Enter the ServicemanMode and perform the Minor Touch – Up Method.24. Perform Sub-Brightness Adjustment procedure ifneeded.0V DCFigure 22. TP35 Waveform2.5V DCFigure 23. Cathode Waveform, AdjustmentWaveform Detail195V DC0V DC (Ground)Service Adjustments (Electronic Controls, cont.)